1. Field of the Invention
The present invention relates to an electronic timepiece having a transmission wheel rotation position detecting unit which detects the position in the rotation direction of a transmission wheel of the electronic timepiece contained in a wheel train thereof such as an obverse wheel train or calendar wheel train.
2. Description of the Prior Art
In a conventional electronic timepiece, as illustrated in FIG. 38, a part of an obverse wheel train 930, e.g., a 24-hour contact point 932 for detecting a rotational position of the obverse wheel train 930 is provided on an hour wheel. When the 24-hour contact point 932 detects the position corresponding to the time of twelve o""clock at night, according to a detection signal output from the 24-hour contact point 932 a circuit block 934 rotates a date driving motor 936. Due to the rotation of the date driving motor 936, a date dial 912 is rotated through a reduction wheel train 938. This makes it possible to change the display of the date.
In the above-described conventional electronic timepiece, in a region near to an outer-peripheral portion of a gear portion of the hour wheel there was provided a conduction pin. And, it was arranged that when the hour wheel rotated, the conduction pin moved a contact point spring so as to cause this contact point to contact with a contact point pattern of the circuit block, and that, when the hour wheel further rotated, the conduction pin was moved away from the contact point spring with the result that the contact point spring was moved away from the contact point pattern of the circuit block. Namely, the contact point spring corresponds to the 24-hour contact point 932 and it was arranged that when the contact point spring contacted with the contact point pattern of the circuit block, the position corresponding to the time of twelve o""clock at night was detected.
Also, in a structure wherein the date driving wheel was rotated through the rotation of the intermediate date driving wheel by the rotation of the date driving motor and the date dial was rotated by the rotation of the date driving wheel, the tooth configuration of the respective gears of the intermediate date driving wheel, date driving wheel and date dial was constituted by a circular arc tooth configuration that includes one or more circular arc portions.
Accordingly, when an external force such as an impact had been applied to the date dial, the rotation of the date dial was stopped by only the index torque of the date driving motor.
However, in the conventional electronic timepiece, there were the problems which follow.
(1) Since the contact point spring was formed of material which was easy to flex, the portion of the contact point spring which contacted with the contact point pattern was difficult to position.
(2) In order to dispose the contact point spring having a sufficient spring length, a significantly large space was needed in the electronic timepiece.
(3) When the portion of the contact point spring which contacts with the contact point pattern is disposed at a position which is farther away from the contact point pattern than necessary, even when the hour wheel rotates, the contact point spring cannot be contacted with the contact point pattern of the circuit block by the conduction pin, with the result that time display or calendar display becomes unable to be accurately made.
(4) When the portion of the contact point spring which contacts with the contact point pattern is disposed at a position which is nearer to the contact point pattern than necessary, when the hour wheel has rotated, the pressure of the contact point spring applied to the conduction pin becomes high, with the result that there is the likelihood that any inconvenience will occur in the operation of the electronic timepiece or the electronic timepiece will inconveniently stop.
(5) The structure of the hour wheel becomes complicated with the result that it becomes necessary to use the contact point spring having a sufficient spring length.
(6) In the conventional calendar equipped electronic timepiece provided at a part of the obverse wheel train with the 24-hour contact point for detecting the rotation position of the obverse wheel train, since a number of wheel trains were disposed between the obverse wheel train and the date dial, it was difficult to achieve an accurate positional coincidence of the date dial due to the backlashes between two adjacent ones of the respective wheel trains.
(7) It was difficult to enhance the precision with which the position in the rotation direction of the hour wheel was detected.
(8) There was the possibility that when an external force such as an impact had been applied to the electronic timepiece, the indication wheel or date dial would rotate. In order to prevent the resulting positional displacement of the date dial, it was needed to increase the index torque of the motor (the stationary force: the torque that resists the rotation when at rest). However, when increasing the index torque of the motor, it resulted that the electric power needed when driving the motor also became increased and as a result the battery life of the electronic timepiece was decreased.
In view of the above, an object of the present invention is to provide an electronic timepiece having a transmission wheel rotation position detecting unit which, in order to solve the above-described conventional problems, detects accurately the position in the rotation direction of the transmission wheel.
Also, another object of the present invention is to provide a small sized electronic timepiece having a transmission wheel rotation position detecting unit.
Further, still another object of the present invention is to provide a small sized and thin type electronic timepiece having a transmission wheel rotation position detecting unit. And,
Further, a further object of the present invention is to provide an electronic timepiece having a transmission wheel rotation position detecting unit whose contact point has a high durability performance.
Also, a yet further object of the present invention is to provide an electronic timepiece which is equipped with a small-sized simplified date driving mechanism and indication wheel detecting mechanism.
Also, a yet further object of the present invention is to provide an electronic timepiece in which even when an external force such as an impact has been applied to the electronic timepiece there is no possibility that the indication wheel or date dial will rotate.
In order to solve the problems, the present invention has been constructed such that an electronic timepiece according thereto comprises a transmission wheel rotating according to the rotation of a wheel train contained in the electronic timepiece, a contact point spring fixed to the transmission wheel and rotating integrally with the transmission wheel and having a conductivity, a detection pattern which is provided on a printed circuit board and, when the contact point spring rotates, can contact with the contact point spring, and a control circuit which inputs a rotational position detection signal for detecting a circumferential position of the rotation of the transmission wheel which, when the contact point spring has contacted with the detection pattern, is output from the detection pattern.
By this construction, the transmission wheel rotation position can be detected using small-sized and simple parts.
Also, in the electronic timepiece according to the present invention, preferably, the detection pattern includes two detection patterns which, when the contact point spring rotates, can simultaneously contact with the contact point spring, and the control circuit which is a control circuit which inputs rotational position detection signals each for detecting the circumferential position of the rotation of the transmission wheel which, when the two detection patterns have been conducted to each other by the contact point spring, are respectively output from the two detection patterns.
By this construction, the rotation position of the transmission wheel can be reliably detected.
Also, in the electronic timepiece according to the present invention, preferably, the detection pattern includes two detection patterns which, when the contact point spring rotates, can simultaneously contact with the contact point spring and nonfunctional patterns provided respectively between the two detection patterns and having no function of detection, and the control circuit which is a control circuit which inputs rotational position detection signals each for detecting the circumferential position of the rotation of the transmission wheel which, when the two detection patterns have been conducted to each other by the contact point spring, are respectively output from the two detection patterns.
By this construction, the durability of the pattern of the printed circuit board can be enhanced.
Further, the present invention has been constructed such that an electronic timepiece according thereto comprises a transmission wheel rotating according to the rotation of a wheel train contained in the electronic timepiece, a contact point spring fixed to the transmission wheel and rotating integrally with the transmission wheel and having a conductivity, and a first detection pattern and second detection pattern which are provided on a printed circuit board and, when the contact point spring rotates, can contact with the contact point spring, whereby it is arranged that the contact point spring and the first detection pattern and second detection pattern can take a first detection state causing only the first detection pattern to generate a rotational position detection signal for detecting a circumferential position of the rotation of the transmission wheel, a second detection state causing only the second detection pattern to generate a rotational position detection signal for detecting a circumferental position of the rotation of the transmission wheel, and a third detection stage causing both the first and the second detection pattern to simultaneously generate rotational position detection signals each for detecting a circumferental position of the rotation of the transmission wheel, and further comprises a control circuit for determining a case where the third detection state has occurred immediately after the first detection state has been detected and a case where the third detection state has occurred immediately after the second detection state has been detected by distinguishing between these two cases.
Also, in the electronic timepiece according to the present invention, preferably, the control circuit is so arranged that when the third detection state has occurred immediately after the first detection state has been detected the control circuit may determine the rotation direction of the transmission wheel as a forward rotation and, when the third detection state has occurred immediately after the second detection state has been detected, may determine the rotation direction of the transmission wheel as a reverse rotation.
Further, in the electronic timepiece according to the present invention, preferably, the printed circuit board further comprises a VDD pattern connected to one potential of a power source, and the contact point spring has three terminal contact point portions which can contact with the first detection pattern, the second detection pattern and the VDD pattern, whereby it is arranged that the contact point spring, first detection pattern and second detection pattern can take a first detection state where, in a state where at least one terminal contact point portion is in contact with the VDD pattern, the other terminal contact point portions are in contact with only the first detection pattern, a second detection state where, in a state where at least one terminal contact point portion is in contact with the VDD pattern, the other terminal contact point portions are in contact with only the second detection pattern, and a third detection state where, in a state where at least one terminal contact point portion is in contact with the VDD pattern, the other terminal contact point portions are in contact with the first detection pattern and second detection pattern, and the control circuit is so arranged that when the third detection state has occurred immediately after the first detection state has been detected the control circuit may determine the rotation direction of the transmission wheel as a forward rotation and, when the third detection state has occurred immediately after the second detection state has been detected, may determine the rotation direction of the transmission wheel as a reverse rotation.
By this construction, the rotation direction of the transmission wheel can be accurately determined.
Also, the present invention has been constructed such that an electronic timepiece according thereto, the electronic timepiece having a function of displaying a date, comprises a time signal generating circuit for generating a time signal by counting data regarding a time, a time indication motor driving circuit which outputs a time indication motor driving signal for rotating a time indication motor, a time indication motor which rotates according to a time indication signal output from the time indication motor driving circuit, a time indication wheel train which rotates according to the rotation of the time indication motor, a time data display member which displays time data according to the rotation of the time indication wheel train, a date signal generating circuit which generates a date signal by counting data regarding a date, a date indication motor driving circuit which outputs a date indication motor driving signal for rotating a date indication motor according to the date signal output from the date signal generating circuit, a date indication motor which rotates according to a date indication signal output from the date indication motor driving circuit, a date indication wheel train which rotates according to the rotation of the date indication motor, a date data display member which displays date data according to the rotation of the date indication wheel train, a date drive start detecting contact point member which detects the point in time at which date drive is started according to the rotation of the time indication wheel train, a date drive termination detecting contact point member which detects the point in time at which date drive is terminated according to the rotation of the date indication wheel train, and a date drive control circuit which controls the operation of the date indication driving circuit outputting the date indication motor driving signal by inputting a signal regarding the start of the date drive which is output from the date drive start detecting contact point member and by inputting a signal regarding the termination of the date drive which is output from the date drive termination detecting contact point member.
By this construction, it is possible to realize a calendar equipped electronic timepiece enabling reliable display of a date.
In the electronic timepiece according to the present invention, preferably, the date indication motor is constituted by an ultrasonic motor.
Also, in the electronic timepiece according to the present invention, preferably, the date drive start detecting contact point member is provided on a 24-hour wheel rotating according to the rotation of a hour wheel, and the date drive termination detecting contact point member is provided on a date driving wheel rotating according to the rotation of the date indication motor.
Further, the present invention has been constructed such that an electronic timepiece according thereto, the electronic timepiece having a function of displaying a date, comprises a time signal generating circuit which generates a date signal by counting data regarding a date, an ultrasonic motor driving circuit which outputs an ultrasonic motor driving signal for driving an ultrasonic motor according to a date signal output from the time signal generating circuit, the ultrasonic motor having an ultrasonic stator having a piezoelectric element bonded thereto and having an ultrasonic rotor which, upon input of the ultrasonic motor driving signal by the piezoelectric element, is friction driven by the oscillatory waves generating in the ultrasonic wave stator due to the expansion and contraction of the piezoelectric element, a calendar wheel train which rotates due to the rotation of the ultrasonic rotor, a date finger which rotates due to the rotation of the calendar wheel train, a date dial which rotates due to the rotation of the date finger and thereby indicates a date, a transmission wheel which rotates due to the rotation of the ultrasonic rotor, a transmission wheel rotating due to the rotation of the ultrasonic rotor, a contact point spring fixed to the transmission wheel and rotating integrally with the transmission wheel and having a conductivity, a detection pattern which is provided on a printed circuit board and, when the contact point spring rotates, can contact with the contact point spring, and a control circuit which inputs a rotational position detection signal for detecting a circumferential position of the rotation of the transmission wheel which, when the contact point spring has contacted with the detection pattern, is output from the detection pattern.
Also, the present invention has been constructed such that an electronic timepiece according thereto, the electronic timepiece having a function of displaying a date, comprises a time signal generating circuit which generates a date signal by counting data regarding a date, an ultrasonic motor driving circuit which outputs an ultrasonic motor driving signal for operating an ultrasonic motor according to a date signal output from the time signal generating circuit, the ultrasonic motor having an ultrasonic stator having a piezoelectric element bonded thereto and having an ultrasonic rotor which, upon input of the ultrasonic motor driving signal by the piezoelectric element, is friction driven by the oscillatory waves generating in the ultrasonic wave stator due to the expansion and contraction of the piezoelectric element, a calendar wheel train which rotates due to the rotation of the ultrasonic rotor and which has a date finger, a date dial which rotates due to the rotation of the date finger and thereby indicates a date, a transmission wheel which is contained in the calendar wheel train and which rotates due to the rotation of the ultrasonic rotor, a contact point spring fixed to the transmission wheel and rotating integrally with the transmission wheel and having a conductivity, a detection pattern which is provided on a printed circuit board and, when the contact point spring rotates, can contact with the contact point spring, and a control circuit which inputs a rotational position detection signal for detecting a circumferential position of the rotation of the transmission wheel which, when the contact point spring has contacted with the detection pattern, is output from the detection pattern.
Further, the present invention has been constructed such that an electronic timepiece according thereto, the electronic timepiece having an indication wheel, comprises a motor for rotating the indication wheel, a rotating member for rotating the indication wheel according to the rotation of the motor, rotation detecting means for generating a signal regarding a state of rotation of the indication wheel according to the rotation of the rotating member, and motor driving means for controlling the rotation of the motor according to a rotation signal generated from the rotation detecting means.
In the electronic timepiece according to the present invention, the rotating member includes an intermediate date driving wheel which rotates according to the rotation of the motor and a date driving wheel which rotates according to the rotation of the intermediate date driving wheel. With regard to this rotating member, the intermediate date driving wheel may be one, or two or more, in number.
The indication wheel is a member which indicates data regarding a time or calendar, and, for example, is a date dial or day indicator.
In the electronic timepiece according to the present invention, preferably, the rotation detecting means includes a contact point spring provided on the rotating member and a plurality of contact point patterns for detecting a state of rotation of the rotating member by contacting with the contact point spring.
By making such construction, it is possible to reliably detect the rotation of the indication wheel. Also, a rotation detecting mechanism of such indication wheel is small in size.
Further, in the electronic timepiece according to the present invention, preferably, it is arranged that the motor is an ultrasonic motor and the motor driving means outputs a drive signal for driving the ultrasonic motor.
When such construction is made, there is no need to provide a number of reduction wheel trains and therefore it is possible to realize a small-sized electronic timepiece equipped with the indication wheel.
Also, the motor may be a step motor or an electromagnetic motor.
Also, in the electronic timepiece according to the present invention, preferably, the indication wheel or date dial has internal teeth which correspond in number to the indication contents and is equipped with a date jumper for regulating the position in the rotation direction of the indication wheel or date dial by engagement thereof with the internal teeth, the rotating member is equipped with four date finger portions for rotating the indication wheel or date dial, it is arranged that the date jumper regulates the position in the rotation direction of the indication wheel or date dial so that one internal tooth of the indication wheel or date dial may be located on a straight line passing through a rotation center of the indication wheel or date dial and a rotation center of the rotating member, and
two of the four date finger portions are positioned, in a state where the ultrasonic motor or motor is being stopped, so as to be located symmetrically about the straight line as a symmetry axis.
And, in the electronic timepiece according to the present invention, preferably, it is arranged that when having been rotated, the date finger can rotate the indication wheel or date dial and, even when having rotated the indication wheel or date dial, the date finger cannot be rotated.
Also, in the electronic timepiece according to the present invention, preferably, it is arranged that through the intermeshing between the internal teeth of the date dial and the date finger as well as through the index torque of the ultrasonic motor or motor the date finger cannot be rotated even when the date dial is rotated.
Further, in the electronic timepiece according to the present invention, preferably, the date finger has lock tooth configurations at its forward end portions.
By making such construction, it is possible to realize an electronic timepiece which enables the decrease in index torque of the ultrasonic motor or motor and enables the effective stop of the rotation of the indication wheel or date dial due to an impact.